MINNEAPOLIS (WCCO) — When flames shot out of a natural gas pipeline in Minneapolis, a lot of us started to wonder about the pipelines beneath our own homes. Is it safe? How do we know?

“Our pipeline system is generally safe, that doesn’t mean there aren’t risk in running our pipeline system,” said Oliver Moghissi, president of NACE International, a trade group of made up of the industry that sells products designed to reduce pipeline corrosion.

According to the Minnesota Office Pipeline Safety, 93 different companies operate pipelines in this state. They carry natural gas, gasoline, oil and other hazardous liquids.

There are more than 65,000 miles of pipeline in Minnesota, but just 12 engineers working for the state to look over it all.

According to federal data, in the decade from 2001-2010, there have been an average of six significant or serious pipeline incidents a year. And a lot of questions about how old these pipeline are.

“In principle, an older pipeline is more likely to have corrosion,” said Moghissi.

The Minnesota Office of Pipeline Safety didn’t have data on the age of our pipelines, but federal government estimates put about 60 percent of all U.S. pipelines at 40 years old or more.

The Minneapolis pipeline that created such a huge fire was installed in 1994, according to CenterPoint Energy, so it was not an older piece of the infrastructure.

Age is not always a major factor in the condition of a pipeline, according to the industry and government experts.

“It doesn’t make me nervous just based on its age. It makes me want to know how the pipeline was maintained and if corrosion has been prevented,” said Moghissi.

Pipeline owners prevent corrosion by coating the steel pipelines and then using an electrical process that keeps rust away. That’s required by the federal government.

But governmental oversight is not enough to keep up with the two million miles of pipe. There are 100 federal inspectors overseeing the whole system. States are responsible for making sure the pipeline owners are on top of things.

Pipeline owners are largely responsible for inspecting their lines — they’ll run water through to look for weak spots, or drop cameras and scanners in there.

In 1986, a gasoline pipeline ruptured in Mounds View resulting in a fire that killed two people. Federal investigators concluded that the pipeline company failed to act on known deficiencies in the line.

Over the past decade, Minnesota has had 58 severe or serious incidents with pipelines. When you just look at the gas lines: there’s an average of two problems a year.

“We rely on this energy transmission and in truth, I think that even though we’ve had some very tragic incidents, the overall record for incidences of failures is low,” said Moghissi.